Claire got her break starring as Amy in BBC1 period drama Little Dorrit

At the age of 13, the previously sporty girl developed juvenile arthritis which left her temporarily crippled and in agony and set her apart from the rest of her schoolgirl pals.

She said: “I was on crutches while the other girls were running around. My knees were swollen while theirs were being shown off in miniskirts.”

The experience gave her confidence a knock.

It was only after the eye tumour at 17 that she applied to study drama at Liverpool John Moores University, and later at the Oxford School of Drama, but it did not automatically transform her into a confident actress.

She said: “I was never the prettiest or the most talented girl. It was always an uphill struggle. I’ve loved drama, but somehow I just thought everyone else was better than me.”

Like most actors, it took her a long time to make her breakthrough, but it came in 2008 when she landed a small part in the pilot of BBC Three drama Being Human, which then saw her get the title role as Amy in BBC1 period drama Little Dorrit, later that year.

After that, the parts steadily rolled in, from the 2010 revival of Upstairs Downstairs, to The Promise in 2011 and Wolf Hall in 2015.